High-precision static pressure main shaft unit

Abstract

The invention relates to a high-precision static pressure spindle unit, and relates to the field of grinding machine static pressure spindles. Comprising a body shell, a static-pressure front bearing, a static-pressure rear bearing, a main shaft and a film feedback adjusting module, the two ends of the body shell are connected with a front hydrostatic bearing and a rear hydrostatic bearing. A front shaft sleeve and a rear shaft sleeve are arranged on the outer circle surfaces of the front hydrostatic bearing and the rear hydrostatic bearing. A front end cover is arranged on the static pressure front bearing; an oil seal and an O-shaped ring seal are arranged among the front end cover, the main shaft and the static pressure front bearing; a film feedback adjusting module is arranged on the outer side of the body shell; an oil inlet main oil way for conveying oil to the static pressure front bearing and the static pressure rear bearing is formed in the body shell, annular grooves in body shell mounting holes corresponding to the front shaft sleeve and the rear shaft sleeve are communicated with the oil inlet main oil way, and the annular grooves and the outer circular surfaces of the shaft sleeves form oil inlet oil cavities; an oil inlet way communicated with the oil inlet cavity is arranged in the body shell, and pressure oil is introduced into the film feedback adjusting module. The static pressure adjusting capacity can be improved, the influence of the axial movement problem of the spindle is reduced, and the application precision of the static pressure spindle in a grinding machine is improved.

Description

Technical Field

[0001] This invention relates to the field of hydrostatic spindles for grinding machines, specifically a high-precision hydrostatic spindle unit. Background Technology

[0002] As the cornerstone of industrial development, the requirements for industrial machine tools are becoming increasingly complex with growing industrial demands. Grinding machines, as a crucial component of industrial machine tools, significantly impact the overall quality of processed products. The spindle, a key component of the grinding machine, determines the machine's load capacity and accuracy.

[0003] To improve grinding accuracy and load capacity, existing grinding machines use hydrostatic spindles to drive the workpiece rotation. Hydrostatic spindles typically employ sliding bearings as the rotation medium, maintaining the spindle's axial position by squeezing fluid within the hydrostatic bearing's oil chamber, thus improving grinding accuracy. However, pressure fluctuations in the hydrostatic oil chamber during operation can cause spindle positional deviations. Therefore, hydrostatic spindles often use throttles to provide a constant pressure environment. Thin-film feedback throttles are widely recognized for their high stability and adaptability; however, their complex structure leads to complex spindle oil circuit design, high cost, and long maintenance times. Furthermore, the significant axial movement of the hydrostatic spindle during operation also affects its accuracy. Therefore, providing a high-precision hydrostatic spindle unit has become a pressing technical problem for those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to design a high-precision hydrostatic spindle unit that adopts an improved thin-film feedback throttle and an optimized oil circuit. The design of the spindle structure is simple, the hydrostatic adjustment capability is improved, and the cost is reduced. At the same time, the improved mechanical structure design and the combination of multiple throttling methods reduce the impact of spindle axial movement, thereby further improving the application accuracy of hydrostatic spindles in grinding machines.

[0005] To achieve the above objectives, the present invention provides a high-precision hydrostatic spindle unit, comprising: a housing, a front hydrostatic bearing, a rear hydrostatic bearing, a spindle, and a diaphragm feedback adjustment module; the front hydrostatic bearing and the rear hydrostatic bearing are respectively fixedly connected to both ends of the housing, and a front shaft sleeve and a rear shaft sleeve are respectively fixedly mounted on the outer circumferential surfaces of the front hydrostatic bearing and the rear hydrostatic bearing, the front shaft sleeve and the rear shaft sleeve forming a clearance fit with the housing; the spindle is installed in the hollow part of the housing, forming a clearance fit with the front hydrostatic bearing and the rear hydrostatic bearing; a front end cover is fixedly installed on the side of the front hydrostatic bearing away from the housing, and the front end cover is respectively connected to the spindle. An oil seal and an O-ring seal are installed between the front hydrostatic bearing and the rear hydrostatic bearing. Two diaphragm feedback adjustment modules are respectively provided on the outer side of the housing corresponding to the positions of the front hydrostatic bearing and the rear hydrostatic bearing. An oil inlet is opened on the upper side slope at the middle position of the housing, and a main oil inlet passage is opened in the housing to supply oil to the front hydrostatic bearing and the rear hydrostatic bearing. An annular groove is set in the housing mounting hole corresponding to the front shaft sleeve and the rear shaft sleeve, and it is connected to the main oil inlet passage. The annular groove and the outer circular surface of the front shaft sleeve and the rear shaft sleeve form an oil inlet cavity. An oil inlet passage connected to the oil inlet cavity is provided in the housing to introduce pressurized oil into the diaphragm feedback adjustment module.

[0006] Furthermore, the diaphragm feedback regulation module includes a diaphragm throttle, a diaphragm feedback oil circuit one, and a diaphragm feedback oil circuit two. The diaphragm throttle includes a diaphragm feedback body, a diaphragm feedback cover, and a diaphragm. The diaphragm feedback body is fixedly installed on the outer side of the housing at the oil inlet positions corresponding to the front and rear axle sleeves. The diaphragm is fixedly installed on the diaphragm feedback body, and the diaphragm feedback cover is fixedly installed above the diaphragm. Grooves are formed on the opposing surfaces of the diaphragm feedback body and the diaphragm feedback cover. The grooves and the diaphragm form two cavities, and the outer rings of the cavities are sealed with O-rings. Each of the two grooves has a boss in the middle. There is a gap between the bosses on both sides of the diaphragm and the two sides of the diaphragm. The cavity of the diaphragm feedback body is provided with a pressure oil channel to the body shell, which is connected to the oil inlet cavity through the oil inlet passage on the body shell. The diaphragm has an oil passage hole at the position corresponding to the oil inlet passage in the cavity. The diaphragm feedback cover has a diaphragm feedback oil passage one, and a through hole is provided at the boss of the diaphragm feedback cover. The diaphragm feedback oil passage one is connected to the body shell feedback oil passage one. The diaphragm feedback oil passage two is provided in the middle part of the boss of the diaphragm feedback body, and is connected to the body shell feedback oil passage two.

[0007] Furthermore, four oil cavities are formed on the inner circular surfaces of both the hydrostatic front bearing and the hydrostatic rear bearing, with multiple oil sealing edges formed around each oil cavity, and an oil inlet pipe opening at the center of each oil cavity; four Z-shaped oil passage pipes are formed on the outer circular surfaces of both the hydrostatic front bearing and the hydrostatic rear bearing; the rear bushing is provided with four oil cavity through holes and one end face oil inlet; the four oil cavity through holes are divided into horizontal and upper and lower groups, the inner ends of the two oil cavity through holes in the horizontal group are connected to the Z-shaped oil passage pipes provided on the hydrostatic rear bearing, and then lead to the two oil cavities at the front and rear of the hydrostatic rear bearing respectively; the outer ends of the two oil cavity through holes in the horizontal group are connected to a thin film feedback adjustment module; the inner ends of the two oil cavity through holes in the upper and lower groups are connected to the Z-shaped oil passage pipes provided on the hydrostatic rear bearing, and then lead to the two oil cavities at the top and bottom of the hydrostatic rear bearing respectively; the outer ends of the two oil cavity through holes in the upper and lower groups are connected to another thin film feedback adjustment module.

[0008] Furthermore, two sealing rings are provided on both sides of the oil inlet chamber to isolate the pressure oil in the oil inlet chamber from the pressure oil in the first feedback oil path and the second feedback oil path of the body shell.

[0009] Furthermore, it also includes an end face thrust adjustment module. The rear end of the main shaft is provided with a collar, and the end face thrust adjustment module is provided outside the collar. A drive plate is fixedly installed at the tail end of the main shaft. The drive plate and the tapered surface at the end of the main shaft are interference-fitted. The outer circle end of the drive plate is connected to a pulley through a threaded pin, and the threaded pin is fitted with an anti-vibration washer. The pulley is rotatably connected to the rear end cover installed behind the housing through a rolling bearing.

[0010] Furthermore, the end face thrust adjustment module includes an end cap, a spacer ring, and two orifice throttle devices; the end face of the hydrostatic bearing and one side of the main shaft ring are clearance-fitted; the spacer ring is fixedly connected to the end face of the hydrostatic bearing, located on the outer ring side of the main shaft ring; the end cap is fixedly connected to the other side of the spacer ring, and the side of the end cap near the spacer ring and the side of the main shaft ring away from the hydrostatic bearing are clearance-fitted; annular grooves are respectively formed on the side of the end cap and the side of the hydrostatic bearing near the main shaft ring; an end face oil inlet main oil passage is formed inside the hydrostatic bearing; end face oil inlet The inner end of the main oil circuit is connected to the oil inlet chamber via the end face oil inlet, and the outer end is connected to the annular groove on the end face of the hydrostatic bearing. An end face oil supply circuit is opened inside the hydrostatic bearing, and its inner end is connected to the end face oil inlet main oil circuit. An oil passage is opened in the spacer ring and connected to the end face oil supply circuit. An end cover oil supply circuit is opened in the end cover and connected to the oil passage, and the end cover oil supply circuit is connected to the annular groove on the end face of the end cover. A small orifice throttle valve one and a small orifice throttle valve two are respectively installed in the end face oil inlet main oil circuit leading to the annular groove on the end face of the hydrostatic bearing and the end face oil supply circuit connected to the oil passage of the spacer ring.

[0011] Furthermore, the inner circular surfaces of the hydrostatic front bearing and the hydrostatic rear bearing, away from the housing, are provided with oil return grooves. Three oil discharge pipes are respectively opened on the lower left and right sides of the oil return grooves, which are connected to the oil discharge pipes opened in the housing. Multiple oil discharge through holes are opened on the inner circular surfaces of the spacer and end cap. Multiple connected oil discharge pipes are opened on the connecting surfaces of the spacer, end cap, and hydrostatic rear bearing, which are connected to the oil discharge pipes in the housing. The oil discharge pipes in the housing are connected to the oil discharge chamber inside the housing. An oil discharge port is opened at the bottom of the housing.

[0012] Furthermore, the spindle was simulated using simulation software, and the clearances between the inner surfaces of the hydrostatic front bearing and the hydrostatic rear bearing and the spindle, the clearances between the front and rear bushings and the housing, the clearances between the diaphragm feedback cover and the diaphragm feedback body boss and the diaphragm, and the clearances between the end face of the hydrostatic rear bearing and the end face of the end cover in the end face thrust adjustment module and the spindle collar were determined.

[0013] The beneficial effects of this invention are as follows: This invention utilizes a diaphragm feedback module to adjust the spindle rotation, adjusting the elastic displacement of the diaphragm by the oil pressure difference between different oil chambers on both sides of the diaphragm. This, in turn, regulates the pressure within the hydrostatic spindle oil chamber, improving the stability of the spindle's working state and enhancing its rotational accuracy. Through the spindle structural design, in conjunction with end caps, spacers, and other components, a hydrostatic end face thrust structure is formed to control the axial movement of the spindle. The design of the bushing simplifies the spindle's oil inlet path and optimizes the spindle's circulation path, reducing maintenance and manufacturing difficulties. In the belt drive, an unloading device is incorporated to prevent the belt's axial force from affecting the spindle's rigidity and rotational accuracy. Through the mutual cooperation between the various structures of the spindle, the spindle becomes more refined, simplified, and precise. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of a high-precision hydrostatic spindle unit according to the present invention; Figure 2 This is a cross-sectional view (AA) of a high-precision hydrostatic spindle unit according to the present invention; Figure 3 This is a cross-sectional view of a thin-film feedback adjustment module of a high-precision hydrostatic spindle unit according to the present invention; Figure 4 This is a three-dimensional front view of the hydrostatic bearing of a high-precision hydrostatic spindle unit according to the present invention; Figure 5 This is a three-dimensional front view of the rear bushing of a high-precision hydrostatic spindle unit according to the present invention; Figure 6 This is a cross-sectional view of the end face thrust adjustment module of a high-precision hydrostatic spindle unit according to the present invention.

[0015] In the diagram: 1-body, 2-front hydrostatic bearing, 3-rear hydrostatic bearing, 4-spindle, 5-pulley, 6-drive disc, 8-vibration damper, 9-rolling bearing, 10-rear end cover, 14-front shaft sleeve, 15-rear shaft sleeve, 16-front end cover, 19-oil cavity, 20-oil sealing edge, 21-diaphragm feedback body, 22-diaphragm feedback cover, 23-diaphragm, 24-cavity, 25-oil passage hole, 26-end cover, 27-spacer ring, 28-small orifice throttle, 29-small orifice throttle II. 30-Oil inlet cavity, 31-Oil cavity through hole, 32-End face oil inlet, 33-O-ring, 110-Main oil inlet circuit, 111-Shell feedback circuit one, 112-Shell feedback circuit two, 113-Membrane feedback circuit one, 114-Membrane feedback circuit two, 115-End face oil supply circuit, 116-Oil passage, 117-End cover oil supply circuit, 118-Oil inlet circuit, 119-Z-type oil circuit pipe, 120-Oil unloading pipe, 121-End face main oil inlet circuit. Detailed Implementation

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0018] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0019] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0020] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0021] See Figure 1 and Figure 2 This embodiment discloses a high-precision hydrostatic spindle unit, including: a housing 1, a front hydrostatic bearing 2, a rear hydrostatic bearing 3, a spindle 4, and a thin-film feedback adjustment module; the two ends of the housing 1 are respectively fixedly connected to the front hydrostatic bearing 2 and the rear hydrostatic bearing 3 by screws; the outer surfaces of the front hydrostatic bearing 2 and the rear hydrostatic bearing 3 are respectively fixedly provided with a front axle sleeve 14 and a rear axle sleeve 15, which are clearance fits with the housing 1; the spindle 4 is installed in the hollow part of the housing 1, and forms a clearance fit with the front hydrostatic bearing 2 and the rear hydrostatic bearing 3; the front end cover 16 is fixedly installed on the side of the front hydrostatic bearing 2 away from the housing 1 by screws, and the front end cover 16 is respectively connected to the spindle 4. An oil seal and an O-ring seal are installed between the front hydrostatic bearing 2 and the rear hydrostatic bearing 3. Two diaphragm feedback adjustment modules are provided on the outer side of the housing 1 at the positions corresponding to the front hydrostatic bearing 2 and the rear hydrostatic bearing 3, respectively. An oil inlet is opened on the upper side slope at the middle position of the housing 1, and a main oil inlet passage 110 is opened in the housing 1 to supply oil to the front hydrostatic bearing 2 and the rear hydrostatic bearing 3. An annular groove is provided in the mounting hole of the housing 1 corresponding to the front shaft sleeve 14 and the rear shaft sleeve 15, and communicates with the main oil inlet passage 110. The annular groove and the outer circular surface of the front shaft sleeve 14 and the rear shaft sleeve 15 form an oil inlet cavity 30. An oil inlet passage 118 is provided in the housing 1 to connect with the oil inlet cavity 30, and pressurized oil is introduced into the diaphragm feedback adjustment module.

[0022] like Figure 3 , Figure 4 and Figure 5As shown, the diaphragm feedback regulation module includes a diaphragm throttle, a diaphragm feedback oil circuit one, and a diaphragm feedback oil circuit two. The diaphragm throttle includes a diaphragm feedback body 21, a diaphragm feedback cover 22, and a diaphragm 23. The diaphragm feedback body 21 is fixedly installed on the outside of the housing 1 at the oil inlet chamber 30 positions corresponding to the front axle sleeve 14 and the rear axle sleeve 15. The diaphragm 23 is fixedly installed on the diaphragm feedback body 21, and the diaphragm feedback cover 22 is fixedly installed above the diaphragm 23. Grooves are formed on the opposing surfaces of the diaphragm feedback body 21 and the diaphragm feedback cover 22. The grooves and the diaphragm 23 form two cavities 24. The outer rings of the cavities 24 are sealed by O-rings 33, and the two grooves... Each groove has a boss in the middle, and there is a gap between the bosses on both sides of the diaphragm 23 and the two sides of the diaphragm 23. The cavity 24 of the diaphragm feedback body 21 is provided with a pressure oil channel to the body shell 1, and is connected to the oil inlet cavity 30 through the oil inlet passage 118 provided on the body shell 1. The diaphragm 23 has an oil passage 25 at the cavity 24 corresponding to the oil inlet passage 118. The diaphragm feedback cover 22 has a diaphragm feedback oil passage 113, and a through hole is provided at the boss of the diaphragm feedback cover. The diaphragm feedback oil passage 113 is connected to the body shell feedback oil passage 111. The diaphragm feedback body boss has a second diaphragm feedback oil passage 114 in the middle part, which is connected to the body shell feedback oil passage 112.

[0023] like Figure 4 As shown, four oil chambers 19 are formed on the inner circular surfaces of both the hydrostatic front bearing 2 and the hydrostatic rear bearing 3, and multiple oil sealing edges 20 are formed around each oil chamber 19. An oil inlet is formed in the middle of each oil chamber 19. Four Z-shaped oil passages 119 are formed on the outer circular surfaces of both the hydrostatic front bearing 2 and the hydrostatic rear bearing 3. Four oil chamber through holes 31 are provided on both the front bushing 14 and the rear bushing 15. The four oil chamber through holes 31 are divided into horizontal and upper and lower groups. The inner ends of the two oil chamber through holes 31 in the horizontal group are connected to the Z-shaped oil passages 119 provided on the hydrostatic rear bearing, and then lead to the two oil chambers 19 at the front and rear of the hydrostatic rear bearing 3, respectively. The outer ends of the two oil chamber through holes 31 in the horizontal group are connected to a thin film feedback adjustment module. The inner ends of the two oil chamber through holes 31 in the upper and lower groups are connected to the Z-shaped oil passages 119 provided on the hydrostatic rear bearing, and then lead to the two oil chambers 19 at the top and bottom of the hydrostatic rear bearing 3, respectively. The outer ends of the two oil chamber through holes 31 in the upper and lower groups are connected to another thin film feedback adjustment module. Figure 5 As shown, the rear bushing 15 is also provided with an end face oil inlet 32.

[0024] The specific structure of the oil cavity through hole 31 communicating with the diaphragm feedback adjustment module is as follows: The boss of the diaphragm feedback body 21 is provided with a second diaphragm feedback oil passage 114, which communicates with the oil cavity through hole 31 of the front axle sleeve 14 or the rear axle sleeve 15 after passing through the second body shell feedback oil passage 112 provided on the body shell 1, and then enters the oil cavity 19 after passing through the Z-shaped oil passage pipe 119; The boss of the diaphragm feedback cover 22 is provided with a first diaphragm feedback oil passage 113, which communicates with the other oil cavity through hole 31 of the front axle sleeve 14 or the rear axle sleeve 15 after passing through the first body shell feedback oil passage 111 provided on the body shell 1, and then enters the oil cavity 19 on the other side after passing through the Z-shaped oil passage pipe 119.

[0025] like Figure 3 As shown, two sealing rings are provided on both sides of the oil inlet chamber 30 to isolate the pressure oil in the oil inlet chamber 30 from the pressure oil in the body feedback oil passage 111 and the body feedback oil passage 212.

[0026] The present invention also includes an end face thrust adjustment module. The rear end of the main shaft 4 is provided with a collar, and the end face thrust adjustment module is provided outside the collar. A drive disc 6 is fixedly installed at the tail end of the main shaft 4. The drive disc 6 and the end of the main shaft 4 are in an interference fit with a tapered surface. The outer end of the drive disc 6 is connected to the pulley 5 through a threaded pin, and the threaded pin is fitted with an anti-vibration washer 8. The pulley 5 is rotatably connected to the rear end cover 10 through a rolling bearing 9. The rear end cover 10 is fixed at the rear of the housing 1, thereby transmitting the belt pressure force to the housing 1 through the rear end cover 10.

[0027] The end face thrust adjustment module includes an end cap 26, a spacer 27, a small orifice throttle valve 28, and a small orifice throttle valve 29. The end face of the hydrostatic bearing 3 and one side of the spindle 4 collar are connected with a clearance fit. The end face of the hydrostatic bearing 3 is fixedly connected to the spacer 27 by screws. The spacer 27 is located on the outer ring side of the spindle 4 collar. The other side of the spacer 27 is fixedly connected to the end cap 26 by screws. The side of the end cap 26 near the spacer 27 and the side of the spindle 4 collar away from the hydrostatic bearing 3 are in clearance fit. Annular grooves are respectively formed on the side of the end cap 26 and the side of the hydrostatic bearing 3 near the spindle 4 collar. An end face oil inlet main oil passage 121 is formed inside the hydrostatic bearing 3. The inner end of the bearing 3 is connected to the oil inlet cavity 30 via the end face oil inlet 32, and the outer end is connected to the annular groove of the end face of the hydrostatic bearing 3. An end face oil supply passage 115 is opened inside the hydrostatic bearing 3, and its inner end is connected to the end face main oil inlet passage 121. An oil passage 116 is opened in the spacer ring 27 and connected to the end face oil supply passage 115. An end cover 26 is opened with an end cover oil supply passage 117 connected to the oil passage 116, and the end cover oil supply passage 117 is connected to the annular groove of the end cover end face. A small orifice throttle valve 128 and a small orifice throttle valve 29 are respectively installed in the end face main oil inlet passage 121 leading to the annular groove of the hydrostatic bearing 3 and the end face oil supply passage 115 connected to the spacer ring oil passage 116.

[0028] Oil enters the annular groove on the end face of the hydrostatic bearing 3 through the end face oil inlet 32, the main oil inlet 121 on the end face, and the small-hole throttle valve 28; oil enters the annular groove on the end face of the end cover through the end face oil supply passage 115, the second small-hole throttle valve 29, the oil passage 116, and the end cover oil supply passage 117. The hydrostatic bearing 3, the spacer 27, and the end cover 26 cooperate with each other to form a thrust structure under the action of the small-hole throttle valve. After the oil fills the thrust structure, when the spindle 4 shaft... During axial movement, the spindle 4 collar moves within the thrust structure, causing a change in the clearance between the two sides of the spindle 4 collar and the end faces of the hydrostatic bearing 3 and end cap 26. This creates a pressure difference in the oil on both sides of the spindle 4 collar, with the side with smaller clearance experiencing greater pressure. The oil then exerts a greater thrust on the spindle 4 collar, pushing the spindle 4 towards a position where the relative forces on both sides of the collar are balanced. This reduces the axial movement of the hydrostatic spindle, thereby improving the stability of the hydrostatic spindle's operation and the spindle's working accuracy.

[0029] Before the main spindle unit operates, the pressurized oil sequentially enters the diaphragm feedback module through the main oil inlet 110, the oil inlet chamber 30, and the oil inlet 118. After passing through the bosses on both sides of the diaphragm 23, it passes through the first diaphragm feedback oil passage 113 and the second diaphragm feedback oil passage 114, and then through the first housing feedback oil passage 111 and the second housing feedback oil passage 112 into a pair of opposing oil chambers 19 in the front and rear bushings and the front and rear hydrostatic bearings, filling the entire oil chamber and gap. During operation, the motor drives the pulley 5 to rotate via the belt, which in turn drives the main spindle 4 to rotate via the drive disc 6. This rotation causes the liquid in the oil chambers 19 of the front and rear hydrostatic bearings to rotate. As the liquid moves from the oil chamber 19 to the sealing edge 20, the change in space and the circumferential symmetry of the oil chambers 19 of the front and rear hydrostatic bearings generate a mutually balancing thrust towards the bearing axis of the main spindle 4, stabilizing the main spindle 4 at the axial position.

[0030] When the spindle 4's axis position deviates, the distance between the spindle 4 and the oil chamber 19 and sealing edge 20 of the hydrostatic front bearing and the hydrostatic rear bearing changes. The relative position thrust on the spindle 4 changes accordingly, causing the flow resistance of the four oil chambers to change. For example, if the thickness of the lower oil film decreases after being loaded, the thickness of the upper oil film increases. Since the sealing edge resistance of the lower oil chamber increases, the pressure in the lower oil chamber increases, and the pressure in the upper oil chamber decreases. Consequently, the lower oil chamber exerts a greater thrust on the spindle 4, pushing the spindle 4 toward the axis position of the hydrostatic bearing.

[0031] During operation, the oil enters the diaphragm feedback body cavity 24 through the main oil inlet passage 110 and the oil inlet passage 118. The diaphragm feedback body is filled with oil. The oil inlet feedback passage and the end face oil inlet passage are separated by the design of the front and rear bushings. The oil enters the front and rear bushings and the hydrostatic front bearing 2 and hydrostatic rear bearing 3 through the oil inlet passage of the diaphragm feedback module. It is then split into the corresponding oil chambers 19 in the Z-shaped oil passage pipes 119 on the outer circle of the hydrostatic front bearing 2 and the hydrostatic rear bearing 3. The oil pressure of the four oil chambers of each bearing corresponds to the diaphragm feedback of two of them. The oil pressure on one side of the diaphragm of the feed body; when the spindle 4 is subjected to external load, the pressure between the oil chambers is different, and the liquid pressure at the two bosses of the diaphragm 23 is also different. Through the throttling feedback module, the gap between one side of the diaphragm 23 and the boss increases, and the throttling resistance between the diaphragm 23 and the boss decreases, thus increasing the oil chamber pressure; the gap between the other side of the diaphragm 23 and the boss decreases, thus decreasing the oil chamber pressure, thereby balancing with the external load, and providing a constant pressure environment for the rotation of the spindle 4, improving the rotational accuracy of the spindle 4, and ensuring the stability of the spindle 4 during operation. At the same time, the diaphragm feedback device is installed on the surface of the housing 1, adopting a split structure, which reduces the maintenance difficulty of the diaphragm feedback device and shortens the maintenance cycle.

[0032] Furthermore, when the oil enters the spindle unit, it enters the oil inlet chamber 30 through the oil inlet passage 118 and then enters the end face main oil inlet passage 121 through the end face oil inlet 32 ​​of the rear bushing 15, thus realizing the oil supply function to the end face thrust bearing. In summary, this invention, through the design of the Z-shaped oil passage pipes of the front and rear bushings and the front and rear bearings, accurately diverts the oil to the corresponding diaphragm side of the diaphragm feedback body in each oil chamber, ensuring the smooth operation of the diaphragm feedback module. At the same time, it separates the end face oil inlet passage from other oil passages, eliminating the need for a separate oil supply system. The oil passage design simplifies the cumbersome oil inlet design in the prior art, more clearly shows the direction of each oil passage, reduces the oil supply pressure of the oil tank, facilitates subsequent oil passage inspection, and reduces the manufacturing and maintenance costs of the spindle unit.

[0033] like Figure 2 , Figure 4 , Figure 6 As shown, the inner circular surfaces of the hydrostatic front bearing 2 and the hydrostatic rear bearing 3, away from the housing 1, are provided with oil return grooves. Three oil discharge pipes 120 are respectively opened on the lower left and right sides of the oil return grooves, connecting to the oil discharge pipes 120 in the housing 1. Multiple oil discharge through holes are opened on the inner circular surfaces of the spacer ring 27 and the end cap 26. Multiple connecting oil discharge pipes 120 are opened on the connecting surfaces of the spacer ring 27, the end cap 26, and the hydrostatic rear bearing 3, connecting to the oil discharge pipes 120 in the housing 1. The oil discharge pipes 120 in the housing 1 connect to the oil discharge chamber inside the housing 1. An oil discharge port is opened at the bottom of the housing 1. Through the design and coordination of multiple oil discharge ports, a large-space oil discharge chamber is set in the middle of the housing 1, which can avoid oil blockage, expand the oil discharge channel, promote oil circulation, and provide conditions for constant pressure in the hydrostatic spindle oil chamber.

[0034] This invention can simulate the spindle 4 using simulation software and determine the gaps between the inner surfaces of the hydrostatic front bearing 2 and the hydrostatic rear bearing 3 and the spindle 4, the gaps between the front bushing 14 and the rear bushing 15 and the housing 1, the gaps between the diaphragm feedback cover 22 and the diaphragm feedback body 21 boss and the diaphragm 23, and the gaps between the end faces of the hydrostatic rear bearing 3 and the end face of the end cover 26 in the end face thrust adjustment module and the spindle 4 collar, etc. By using simulation software, the specific gap ranges between each part can be determined, allowing for precise control of gaps during assembly. Through gap control, the specific performance of the spindle 4 can be fine-tuned, bringing the spindle 4 to its optimal state, avoiding material waste, reducing costs, and achieving refined design of the spindle unit.

[0035] This invention utilizes a diaphragm feedback module to adjust the spindle rotation, adjusting the elastic displacement of the diaphragm by the oil pressure difference between different oil chambers on both sides of the diaphragm. This, in turn, regulates the pressure within the hydrostatic spindle oil chamber, improving the stability of the spindle's working state and enhancing its rotational accuracy. Through the spindle structural design, in conjunction with end caps, spacers, and other components, a hydrostatic end face thrust structure is formed to control the axial movement of the spindle. The design of the front and rear bushings simplifies the oil inlet path of the spindle unit and optimizes the circulating oil path, reducing maintenance and manufacturing difficulties. In the belt drive, an unloading device is incorporated to prevent the belt's axial force from affecting the spindle's rigidity and rotational accuracy. Through the mutual cooperation between the various structures of the spindle unit, the spindle unit becomes more refined, simplified, and precise.

[0036] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A high-precision hydrostatic spindle unit, characterized in that, include: The structure comprises a housing (1), a front hydrostatic bearing (2), a rear hydrostatic bearing (3), a main shaft (4), and a thin-film feedback adjustment module. The housing (1) is fixedly connected to the front hydrostatic bearing (2) and the rear hydrostatic bearing (3) at both ends. A front axle sleeve (14) and a rear axle sleeve (15) are fixedly mounted on the outer surfaces of the front hydrostatic bearing (2) and the rear hydrostatic bearing (3), respectively. The front axle sleeve (14) and the rear axle sleeve (15) are connected to the housing (1) with a clearance fit. The main shaft (4) is installed in the hollow portion of the housing (1) and forms a clearance fit with the front hydrostatic bearing (2) and the rear hydrostatic bearing (3). A front end cover (16) is fixedly mounted on the side of the front hydrostatic bearing (2) away from the housing (1). The front end cover (16) is connected to the main shaft (4) and the front hydrostatic bearing (2) with a clearance fit. Install oil seals and O-ring seals; the outer side of the housing (1) is provided with two diaphragm feedback adjustment modules at the positions corresponding to the front hydrostatic bearing (2) and the rear hydrostatic bearing (3); an oil inlet is opened at the upper side slope of the middle position of the housing (1) and a main oil inlet passage (110) is opened in the housing (1) to supply oil to the front hydrostatic bearing (2) and the rear hydrostatic bearing (3); an annular groove is set in the mounting hole of the housing (1) corresponding to the front shaft sleeve (14) and the rear shaft sleeve (15) and communicates with the main oil inlet passage (110); the annular groove and the outer circle surface of the front shaft sleeve (14) and the rear shaft sleeve (15) form an oil inlet cavity (30); the housing (1) is provided with an oil inlet passage (118) that connects to the oil inlet cavity (30) to pass the pressure oil into the diaphragm feedback adjustment module.

2. The high-precision hydrostatic spindle unit as described in claim 1, characterized in that, The diaphragm feedback adjustment module includes a diaphragm throttle, a diaphragm feedback oil circuit one, and a diaphragm feedback oil circuit two. The diaphragm throttle includes a diaphragm feedback body (21), a diaphragm feedback cover (22), and a diaphragm (23). The diaphragm feedback body (21) is fixedly installed on the outside of the housing (1) at the oil inlet chamber (30) of the corresponding front axle sleeve (14) and rear axle sleeve (15). The diaphragm (23) is fixedly installed on the diaphragm feedback body (21), and the diaphragm feedback cover (22) is fixedly installed above the diaphragm (23). The diaphragm feedback body (21) and the diaphragm feedback cover (22) have grooves on their opposite surfaces. The grooves and the diaphragm (23) form two cavities (24). The outer ring of the cavity (24) is sealed by an O-ring (33), and the two grooves... Each of the two sides of the membrane (23) has a boss, and there is a gap between the boss and the membrane (23). The cavity (24) of the membrane feedback body (21) is provided with a pressure oil channel to the shell (1), and is connected to the oil inlet cavity (30) through the oil inlet passage (118) provided on the shell (1). The membrane (23) has an oil passage (25) at the cavity (24) corresponding to the oil inlet passage (118). The membrane feedback cover (22) has a membrane feedback oil passage one (113), and a through hole is provided at the boss of the membrane feedback cover. The membrane feedback oil passage one (113) is connected to the shell feedback oil passage one (111). The membrane feedback body boss has a membrane feedback oil passage two (114) in the middle, which is connected to the shell feedback oil passage two (112).

3. The high-precision hydrostatic spindle unit as described in claim 2, characterized in that, Four oil chambers (19) are opened on the inner circular surface of both the hydrostatic front bearing (2) and the hydrostatic rear bearing (3), and multiple oil sealing edges (20) are formed around each oil chamber (19). An oil inlet is opened in the middle of each oil chamber (19); four Z-shaped oil passages (119) are opened on the outer circular surface of both the hydrostatic front bearing (2) and the hydrostatic rear bearing (3); four oil chamber through holes (31) and one end face oil inlet (32) are provided on the rear bushing (15); the four oil chamber through holes (31) are divided into horizontal and upper and lower groups, and the two oil chamber through holes in the horizontal group ( 31) After the Z-shaped oil passage (119) set on the inner end and the static pressure bearing is connected, it is connected to the two oil chambers (19) before and after the static pressure bearing (3); the outer ends of the two oil chamber through holes (31) of the horizontal group are connected to a thin film feedback adjustment module; the inner ends of the two oil chamber through holes (31) of the upper and lower groups are connected to the Z-shaped oil passage (119) set on the static pressure bearing, and are connected to the two oil chambers (19) above and below the static pressure bearing (3); the outer ends of the two oil chamber through holes (31) of the upper and lower groups are connected to another thin film feedback adjustment module.

4. A high-precision hydrostatic spindle unit as described in claim 2 or 3, characterized in that, Two sealing rings are provided on both sides of the oil inlet chamber (30) to isolate the pressure oil in the oil inlet chamber (30) from the pressure oil in the body feedback oil path one (111) and the body feedback oil path two (112).

5. A high-precision hydrostatic spindle unit as described in claim 4, characterized in that, It also includes an end face thrust adjustment module. The rear end of the main shaft (4) is provided with a collar, and the end face thrust adjustment module is provided outside the collar. The tail end of the main shaft (4) is fixedly installed with a drive plate (6). The drive plate (6) and the end of the main shaft (4) are in a tapered interference fit. The outer circle end of the drive plate (6) is connected to the pulley (5) through a threaded pin, and the threaded pin is fitted with an anti-vibration washer (8). The pulley (5) is rotatably connected to the rear end cover (10) installed behind the body shell (1) through a rolling bearing (9).

6. A high-precision hydrostatic spindle unit as described in claim 5, characterized in that, The end face thrust adjustment module includes an end cap (26), a spacer (27), a small orifice throttle valve one (28), and a small orifice throttle valve two (29); the end face of the hydrostatic bearing (3) and one side of the main shaft (4) collar are connected with clearance fit, the end face of the hydrostatic bearing (3) is fixedly connected to the spacer (27), the spacer (27) is located on the outer ring side of the main shaft (4) collar, the other side of the spacer (27) is fixedly connected to the end cap (26), the side of the end cap (26) near the spacer (27) and the side of the main shaft (4) collar away from the hydrostatic bearing (3) are connected with clearance fit; the side of the end cap (26) and the side of the hydrostatic bearing (3) near the main shaft (4) collar are respectively provided with annular grooves; the end face oil inlet main oil passage (121) is provided in the hydrostatic bearing (3); the end face oil inlet main oil passage (121) is provided with... The end face oil inlet (32) is connected to the oil inlet cavity (30), and the outer end is connected to the annular groove of the end face of the hydrostatic bearing. The end face oil supply passage (115) is opened in the hydrostatic bearing (3), and its inner end is connected to the end face main oil inlet passage (121). The spacer (27) is opened with an oil passage (116) and connected to the end face oil supply passage (115). The end cover (26) is opened with an end cover oil supply passage (117) connected to the oil passage (116), and the end cover oil supply passage (117) is connected to the annular groove of the end face of the end cover (26). The end face main oil inlet passage (121) of the hydrostatic bearing (3) leading to the annular groove of the end face of the hydrostatic bearing and the end face oil supply passage (115) connected to the spacer oil passage (116) are respectively equipped with a small hole throttle valve one (28) and a small hole throttle valve two (29).

7. A high-precision hydrostatic spindle unit as described in claim 6, characterized in that, The front hydrostatic bearing (2) and the rear hydrostatic bearing (3) have an oil return groove on the inner circular surface away from the housing (1). Three oil discharge pipes (120) are opened on the lower left and right sides of the oil return groove, which are connected to the oil discharge pipes (120) opened in the housing (1). Multiple oil discharge through holes are opened on the inner circular surface of the spacer (27) and the end cap (26). Multiple connected oil discharge pipes (120) are opened on the connecting surface of the spacer (27), the end cap (26), and the rear hydrostatic bearing (3), which are connected to the oil discharge pipes (120) in the housing (1). The oil discharge pipes (120) in the housing (1) are connected to the oil discharge chamber in the housing (1). An oil discharge port is opened at the bottom of the housing (1).

8. A high-precision hydrostatic spindle unit as described in claim 7, characterized in that, The spindle (4) was simulated using simulation software, and the gaps between the inner surfaces of the hydrostatic front bearing (2) and the hydrostatic rear bearing (3) and the spindle (4), the gaps between the front bushing (14) and the rear bushing (15) and the housing (1), the gaps between the boss of the diaphragm feedback cover (22) and the diaphragm feedback body (21) and the diaphragm (23), and the gaps between the end face of the hydrostatic rear bearing (3) and the end face of the end cover (26) and the collar of the spindle (4) were determined.

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